This invention relates to a cold starting aid system for internal combustion engines.
Air-cooled internal combustion engines are employed in a variety of applications in everyday life, from mopeds to family transport, large trucks, and industrial power plants. Today""s engines are designed to operate reliably within a limited temperature range, typically between xe2x88x9220xc2x0 C. to 40xc2x0 C. When faced with extreme operating conditions, such as low temperatures, consistent engine start up and operation cannot be relied upon without assistance.
In order to initiate the combustion of an air/fuel mixture in a combustion chamber of an engine, the internal energy of the mixture must be raised to a critical level. For gasoline engines, this is typically accomplished through a compression of the air/fuel mixture and a subsequent ignition supplied by a spark plug. If the engine start up is not achieved immediately, then power, supplied by a battery is used to crank the engine over an extended period of time until the engine starts. In extreme cold conditions, a block heater can sometimes be relied upon, to warm up the engine block and, thereby, raise the internal energy of the fuel and air closest to the combustion chamber, in combination with the compression cycle and the ignition spark. The disadvantages of this start up aid is that it expends energy not used during start up, it requires time to warm up the engine block before starting can be tried, and an external energy source must be used to power the block heater. It is not uncommon for the battery to run out of charge at extreme cold temperatures before achieving start up.
In operation with diesel engines in extreme temperature conditions, raising the internal energy of the air/fuel mixture is accomplished by compression of the air/fuel mixture only, or by compression and the use of an electric glow plug. These starting systems are suitable only for smaller size engines with high compression ratio and high RPM (automobile diesel engines). Larger engines, like the ones of transport trucks, require different starting aids. Some are using the same block heaters as for the gasoline engines. The block heaters are not usually relied upon because of inaccessibility en-route (no external power source to connect the heater). Therefore, at low temperatures, it is not uncommon to leave the engine running rather than risk restart. Also, the use of a block heater is practical where the engine is water-cooled, but in some applications air cooled engines are preferred. The start up of diesel engines can also experience other disadvantages, namely running down of the battery, extended start up times, and excessive use of power resources.
One startup aid for diesel engines is to heat the intake air with fuel-fired (combusting) glow plugs. This starting aid is reliable only if the engine draws excess amounts of air through its intake manifold to supply oxygen to both the fuel fired glow plugs and a fuel charge in the combustion chamber. Otherwise, the fuel-fired glow plug can consume all the oxygen in the air and xe2x80x9cstarvexe2x80x9d the engine.
A particular problem arises where an internal combustion engine is used to drive stationery equipment, e.g. a generator or pump. Such devices are used intermittently and may remain idle or in storage for extended periods. The devices typically are transported to a remote location and the engine must be able to start quickly and reliably without significant preparation.
It is therefore an objective of the present invention to provide a cold starting aid system and a starting method that will obviate or mitigate the above disadvantages.
In general terms, the present invention relates to a cold start system for internal combustion engines and its method of use. In one aspect of the invention, there is provided a cold start system for an engine having at least one fuel injector and an air intake manifold to supply fuel and air respectively, into a combustion chamber. The cold start system includes at least one heating element to be disposed in the air intake manifold to heat a body of air and at least one heating element to be disposed around the fuel injector to heat the fuel contained therein.
Preferably, a controller, including a series of switches, is used to regulate a supply of power from a battery to the starter, and the plurality of heating elements. The controller is connected to a microprocessor with associated power management software. The software directs the controller by way of a feed back loop connected to an ambient temperature sensor, to select an appropriate heating and cranking cycle. Additional sensors can be incorporated into the controller and include a RPM sensor which detects if the engine has started, an oil pressure sensor which monitors the pressure of the oil, a water sensor which detects if there is water present in the fuel, and a range RPM sensor which detects if the speed of the engine is outside of the normal operating range.
In a preferred embodiment, a fuel pre-heat system consists of a heater body mounted around the fuel injector. The body houses the fuel injector and a thermally conductive gasket may be positioned between the body and the fuel injector, to enhance heat transfer there between. A plurality of heating elements are inserted into a series of holes located around an exterior of the body, which minimizes the distance between the fuel pre-heat system and the combustion chamber.
An air pre-heat system of a preferred embodiment includes a spacer located in the air intake manifold and a plurality of heating elements. A series of ports are preferably located in a peripheral wall of the spacer, into which the heater elements are inserted. A thermal insulator may be positioned between the spacer and the air intake manifold. A plurality of insulating fasteners are used to mount the spacer to the air intake manifold and minimize heat transfer.